1. Field of the Invention
The present invention relates to optical disc drives, and more particularly, to tracking error signal generated in optical disc drives.
2. Description of the Prior Art
An Optical sensor on a pick-up head (PUH) of an optical disc drive can be divided into four parts A, B, C, and D. When an optical disc is being read or written, the above-mentioned four parts A, B, C, and D detect light beams reflected from the optical disc to generate corresponding signals A, B, C, and D, and utilize phase information generated when the PUH deviates from an optical disc track to obtain a tracking error signal TE, which is supplied to a servo controller. A typical phase detection method utilizes a phase comparator to determine a phase difference between the signals A and B, utilizes another phase comparator to determine a phase difference between the signals C and D, and then synthesizes the two signals representing phase difference to generate the required tracking error signal. However, the phase difference between the signals A and B and the phase difference between the signals C and D do not contain tracking error information of equal significance at every instance. When one is more significant than the other, a tracking error signal generated by simply adding the two may not be the best representation of the tracking error information.